The present invention relates to a multi-chamber container having at least two compartments for storing hemodialysis concentrates that, when diluted and mixed, serve to absorb toxic substances from the blood of patients suffering from renal disorders. More specifically, one compartment contains a first partial concentrate of glucose, and the other compartment contains a second partial concentrate of electrolytes and hydrochloric acid.
Different types of multi-chamber containers are known, and are designed to hold different solutions in their compartments. While these solutions must be dispensed in mixed form, they are often storage incompatible. For this reason, the individual compartments of these multi-chamber containers are separated until just before the application of the solutions. In some cases, liquid communication channels are provided between the compartments, and are opened just prior to application so that the liquids can be mixed.
The fluid communication channel used in a multi-chamber container can be a breakable connector or a peelable seal, as described in German patent DE 44 10 876 C. The peelable seal opens as the result of pressure on the container so that the solutions can be easily mixed with one another in a single space, without dead volume. A typical application of such multi-compartment containers can be found in the field of renal dialysis, especially peritoneal dialysis, where solutions serve as the absorption medium for the body""s toxic substances as a replacement for non-functional kidneys.
Such solutions comprise a buffer system, which is brought into the physiological region with an acid, and an electrolyte solution. Bicarbonate is a known buffer for blood. Accordingly, this buffer is generally chosen for hemodialysis solutions. Acetic acid is widely used as the acid, as it can be broken down in the citric acid cycle. To avoid any change in the vital electrolyte concentrations in the body of the patients, calcium ions and potassium ions, generally in the form of their chlorides, are added to the solutions. Also added are relatively high concentrations of common salt (NaCl). In general, glucose is used as the osmosis medium to generate the pressure which effects or at least accelerates the exchange of materials.
The separate storage of individual components that lack compatibility has been described in the prior art. German patent DE 39 17 251 C, for example, shows a two-chamber container system for the manufacture of a peritoneal dialysis solution, containing a concentrated acid solution with at least calcium ions in one chamber and a bicarbonate solution in a second chamber. In that reference, there is a risk of calcium carbonate, which is difficult to dissolve, being formed and precipitated in the solution if the components are stored together. For this reason, the calcium and the bicarbonate are stored separately and are only mixed just before being used in the procedure.
For the above reasons, it has become customary to store the bicarbonate separately from the other components of a hemodialysis solution. To save transportation and storage costs, it is also advisable to make the components available at the place of treatment in concentrated form when possible. For this reason, it has been proposed to provide the bicarbonate as a solid substance in a cartridge separate from all other components. See Patent Application No. EP 0 278 100 A. The NaCl is an easily soluble salt, and also lends itself to be provided in solid form, as a separate unit.
When the components are provided in powdered form, it is necessary to store the powders separately because if the powders are mixed fluctuations in concentration can arise in the course of the dissolving process due to different solubility rates. It is advantageous to provide the acid, the electrolytes and the glucose in a solid form. However, in practice, this is prevented by problems of solubility and dosage. On the one hand, the electrolytes are too hygroscopic and, on the other hand, acids such as conventionally used acetic acid are liquid at room temperature. For these reasons, the current procedure has been to make these components available as high concentration liquids to lower transportation costs.
It is also necessary to separate the components of solutions containing glucose, because the heat sterilization of such solutions can cause a breakdown of the glucose. Patent WO 93/09820 proposes to accommodate the glucose in a first compartment of a container in a solution having a glucose content of at least 10%, and provide a pH of around 3.5 by adding an acid. The breakdown of the glucose during sterilization of such mixture is thus prevented by the acid. The electrolytes and a lactate buffer can then be located in the second compartment of the container.
It has been found in the course of medical practice that acetic acid and other acids which can be broken down in the citric acid cycle show clinical side effects, for example, they can result in acidosis. For this reason, it has become customary to use acetate-free dialysis fluids. One physiologically compatible acid which is used in dialysis is hydrochloric acid. Hydrochloric acid is a strong acid, and is displaced when bicarbonate is introduced as the buffer system. This is because carbon dioxide can easily be formed during the mixing. Furthermore, hydrochloric acid has the disadvantage of not being heat-sterilizable, because HCl volatilizes too easily into a gas and has a highly corrosive effect.
The present invention relates to a container that provides a concentrated hemodialysis solution that allows acetate-free dialysis. The multi-chamber container in accordance with the invention comprises a flexible, biocompatible and transparent material, preferably made of polyolefins, and has a first compartment containing concentrated glucose and a second compartment containing concentrated hydrochloric acid, including calcium ions, magnesium ions and potassium ions and chlorides. The two compartments are separated by a peelable separating seal. The peelable seal is opened shortly before use by pressure on the two chambers, so that the two concentrates are mixed. A connection can also be placed between the two components. For example, a connector can be provided with a predetermined breaking point, which opens a liquid conduit upon being broken.